DE1668999B - Process for the catalytic disproportionation of acyclic olefins - Google Patents

Description

the general formula

; C = C <R (R ₁ ) C = C (R ₈ ) R ₃

rs C ²⁰

, wherein the radicals R to R _{3 are} hydrogen atoms or

Mean alkyl or aryl radicals in a mixture with slightly

or secondary olefins with the grouping of polymerizable tertiary olefins with the group -Ar - CH = Cc, in which Ar is an aromatic pierung
Remainder means, reacts with catalysts, with 25
the aluminum oxide serving as a carrier or the ^ _- J,

from rhenium heptoxide to aluminum oxide

standing catalyst by adding a small amount of C = Cc

Amount of alkali or alkaline earth metal ions modi rs C

has been fected. 30th

2. The method according to claim 1, characterized in that a catalyst is used, or secondary olefins with the grouping 0.1 to 40 parts of rhenium heptoxide per 100 parts of Ar - CH = C c, where Ar is an aromatic red Contains aluminum oxide. means, reacts with catalysts, the as

3. The method according to claim 1 and 2, characterized in that 35 aluminum oxide serving as a carrier or the one from Rhege characterized, that a catalyst of ammonium heptoxide on aluminum oxide is used, the 0.02 to 5 percent by weight alkali analyzer by adding a small amount of alkali or Contains alkaline earth metal ions. or alkaline earth metal ions has been modified.

4. The method according to claim 1 to 3, characterized in that it contains commercially available aluminum oxide characterized in that the starting mixture as 40 usually alkali metal ions in a small amount, easily polymerizable olefin contains isobutene. z. B. about 0.03 weight percent sodium ions, the

originate from the manufacturing process. However, the invention is based on the finding that selectively

tive catalysts can be obtained if the

45 Rhenium heptoxide on aluminum oxide-containing catalyst or the aluminum object of Belgian patent 672 589 serving as a carrier is a miniumoxide before the combination with the rhenium process for the production of olefins, which is characterized by a low proportion of alkali or earth oxide heptoxide, that one a starting mixture of alkali metal ions over and above the amount added two dissimilar acyclic olefins that will give formulas 50, from the manufacturing process already before-D / -D -w- _ / ~ yd Μ? jn _iD s _n rvD id is available. It is believed that the alkali or

K (KJC - C (K ₂ JK ₃ and K ₄ (K ₅ ) C - C (K ₆ ) K ₇₎ alkaline earth metal ions on the surface of the support

have, in which the substituents R for hydrogen are deposited.

atoms or alkyl or aryl radicals, but the catalyst advantageously contains 0.1 to 40, not more than two of the groups R (R ₁ ) Cc, 55 preferably 1 to 20 parts of rhenium heptoxide per R ₃ (R ₂ ) Cc, R ₄ (R ₅ ) Cc or R ₇ (R ₆ ) Cc are the same, 100 parts of aluminum oxide.

in the presence of an olefin disproportionation catalyst. The optimal content of metal ions depends on the

lysators. Choice of the metal ion. Catalysts that one too

A disproportionation catalyst is a catalyst that contains a small amount of the metal ion, retained sator, which converts an olefin into a mixture of olefins, some of which have their polymerization activity, while lower and higher carbon numbers than the catalysts, which are too large Metal ion amount escaped olefin capable of converting. From the British hold, a lesser catalytic effect on the patent specification 1,054,864 are disproportionation coreactions of olefins,
catalysts for the disproportionation of acyclic As alkali or alkaline earth metal ions Na-

Olefins known, which are preferred from rhenium heptoxide to aluminum, potassium and calcium ions. In consist of miniumoxide as a carrier. In these cases, the catalyst should be 0.02 to 5.0

Certain olefins, e.g. B. isobutene, polymerize weight percent, preferably 0.1 to 1.0 weight known very easy. For this reason, it has so far been included as a percentage of added metal ions.

The incorporation of the alkali or alkaline earth metal ions into the catalyst support for the purpose of Invention can be done in a known manner, e.g. B. by treating the carrier with an aqueous Separating a solution of an alkali salt such as sodium carbonate, sodium bicarbonate or sodium acetate the solid catalyst from the liquid medium and subsequent drying.

Before being used for the reaction, the catalysts can be subjected to thermal activation either in flowing inert gas, such as nitrogen, carbon dioxide or helium, or preferably in flowing air or flowing oxygen with subsequent aftertreatment in an inert gas. The catalysts are advantageously from 1 minute to 20 hours treated in air at a temperature in the range from 300 to 900 ⁰ C and under similar conditions with eineir "inert gas such as nitrogen.

Is preferred as an easily polymerizable olefin Isobutene used. A very suitable feedstock for the process is a mixture which is im consists essentially of 3uten-2 and isobutene, since the reaction products, namely propylene and 2-methylbutene-2, are very sought-after olefins.

The conditions under which the olefins react will vary with the composition of the feed and the desired products. The reaction temperatures can be in the range from -20 to 500 ° C. T.mperatures im Range from 20 to 100 ° C.

The reaction pressures can range from 0 to

14 atü lie.

In a continuous process, the reaction times can be between 0.01 seconds and 120 minutes lie. They are preferably 0.1 second to 10 minutes.

In a batch process, there are weight ratios of olefin to catalyst in the range from 1000: 1 to 1: 1 in question.

The process can optionally be carried out in the presence of an inert diluent, e.g. B. a paraffinic or cycloparaffinic hydrocarbon.

The procedure is illustrated by the following examples. The experiment described in Example 1 was not carried out according to the method according to the invention and is only used for comparison.

example 1

Into a vertical silica tube 30 cm long and 12 mm inside diameter were] from below top 1 cm quartz wool, 2.70 g ammonium perrhenate, 1 cm quartz wool, 5 cn. ·. Silica shavings a particle size of 0.5 to 0.84 mm and

15 g of aluminum oxide, which had previously been ^{activated at 600 °} C., filled. The aluminum oxide was a poorly crystalline aluminum oxide, which had a surface area of 200 m ² / g, a pore volume of 0.32 ml / g and an average pore diameter of 67 Å.

The upper zone of alumina v.arde in a stream of dry air heated the enough to keep the bed in a fluidized bed at 550 ⁰ C. A heating furnace was then brought downstairs to heat the ammonium perrhenate, which was decomposed to rhenium beptoxide which was then volatilized

ίο ui.d was carried by the air stream into the fluidized bed of aluminum oxide at 550 ⁰ C. The heating and vortexing were carried out for 4 hours from the time the oven was moved down to decompose the perrhenate.

The catalyst prepared in this way contained 14 percent by weight rhenium heptoxide and 0.03 percent by weight Sodium ions.

A feed containing 6.4 weight percent butene-1, 42.4 percent by weight isobutene and 51.2% butene-2 contained, was then at 20 ° C, 10.5 atmospheres and a space flow rate of 10 V / V / hour (based on the liquid state) over the Catalyst passed. The results are given in the table below.

^a5 example 2

An aqueous solution of O ^ Sn sodium bicarbonate was passed continuously over a further sample of the alumina described in Example 1 for 25 hours at ambient temperature. The solid was then filtered and dried at HO ⁰ C dried.

The experiment described in Example 1 was then carried out using the with Natriuf. treated alumina repeated in place of the previously used, untreated aluminum oxide. The catalyst contained 0.25 weight percent sodium ions. The results are given in the following table.

Products
40 example 1
g / 100 g insert Example 2
g / 100 g insert Ethylene
Propylene
Biiten-1
45 isobutene
Butene-2
n-pentenes
Isopentenes
Polymer *
50 total 0.3
15.5
1.3
22.6
32.2
4.6
16.6
6.8
99.9 0.4
16.7
1.3
25.7
32.9
4.2
18.3
0.4
99.9

* Mainly butene oligomers.

A comparison of the examples shows that the sodium treated catalyst promotes polymer formation and the co-reaction of the olefins used increased, as did the increased proportion of propylene and isopentenes in the product obtained according to Example 2 shows.

Claims (1)

it has not been possible to convert mixtures of olefins that contain an easily polymerizable olefin over a disproportionation catalyst, 1. Process for catalytic disproportionation without substantial polymerization of the use of acyclic olefinic hydrocarbon 5 material takes place. substances in the presence of a rhenium heptoxide. It has now been found that the addition of Aluminum oxide catalyst, thereby reducing the amount of alkali or alkaline earth metal ions indicates that monoolefins of the known rhenium heptoxide-aluminum oxide cata- general formula lysers can be modified so that the poly Rn? \ c - cm IR ¹⁰ merization activity considerably in favor of a higher one K (K ₁ ) CU (Ks ₁ ) K ₃ disproportionation can be reduced. wherein the radicals R to R ₃ hydrogen atoms or * The invention is a process for alkyl or aryl radicals, in a mixture with catalytic disproportionation of acyclic easily polymerizable tertiary olefins with the olefinic hydrocarbons in the presence of a grouping 15 rhenium heptoxide on aluminum oxide catalyst which is characterized in that one monoolefins